In power transmission networks, equipment is often connected to high potential relative ground. For example, platforms are used when capacitors are provided in series with high voltage transmission lines.
There is typically equipment onboard the platform which is used for protection, control and monitoring purposes. For example, current measuring systems can be used to convert analogue measured data to digital form and transmit them to ground level by data transmission via optical fibre. Other equipment is used to bypass the capacitor bank when the line current becomes too high due to short-circuits in the power transmission system. Auxiliary power is required for actuators and similar devices.
Auxiliary power for measurement systems that require only a fraction of a watt may be supplied through fibres from lasers on ground potential. However, equipment that includes fast-acting actuators for protection purposes, necessitates substantial amount of energy that is stored on high potential. If charging of the energy storage must be performed in a reasonable time (minutes) substantial power (hundreds of watts) must be provided.
Consequently, there is a need to improve how power is supplied to loads on platforms with high potential relative to ground.